Headrest position adjusting device, and headrest position adjusting method

Abstract

Head restraint position adjusting device 100 includes: capacitance sensor unit 10 including plural sensing electrodes 11 to 15 and detection circuit 20; and drive motor unit 30 including motor drive circuit and drive motor. Sensing electrodes 11 to 15 are formed in a rectangular strip having its longer side exist in width direction of front face of head restraint 43 intersecting with height direction, and arranged such that their longer sides are lined up in height direction. Detection circuit 20 includes plural capacitance sensing circuits 21 to 25 connected in one-to-one to sensing electrodes 11 to 15 and arithmetic processing circuit 28. Even in initial condition of head restraint 43, estimated center position of head 49 a of human body 49 in height direction can be obtained even if detection circuit 20 detects neck 49 b and shoulder 49 c from sensing signals of sensing electrodes 11 to 15, leading to highly precise position adjustment in short time.

1 . A head restraint position adjusting device, comprising:
 a plurality of sensing electrodes provided side by side in a height direction in a head restraint provided on a seat of a vehicle and configured to sense capacitances between a human body sitting on the seat and the head restraint;   a detection circuit configured to detect an estimated center position of a head of the human body in the height direction based on sensing signals from the plurality of sensing electrodes; and   position adjusting means configured to, in accordance with a detection result from the detection circuit, adjust a position of the head restraint relative to the seat based on the estimated center position;   in a case (a) where there is any sensing electrode that indicates a larger capacitance value than that of its adjoining sensing electrode located under it among sensing electrodes located above a largest value sensing electrode, which has sensed a capacitance indicating a largest capacitance value among capacitance values of capacitances sensed by the respective sensing electrodes, the detection circuit being configured to detect as the estimated center position, a position that horizontally corresponds to a sensing electrode that has sensed a capacitance indicating a largest capacitance value among capacitance values of capacitances sensed by any such sensing electrodes that indicate a larger capacitance value, and   in any other case than the case (a), the detection circuit being configured to detect a position that horizontally corresponds to the largest value sensing electrode as the estimated center position.   
   
   
       2 . The head restraint position adjusting device according to  claim 1 , wherein in a case where the largest value sensing electrode is located above a predetermined sensing electrode, the detection circuit detects a position that horizontally corresponds to the largest value sensing electrode as the estimated center position among the plurality of sensing electrodes. 
   
   
       3 . The head restraint position adjusting device according to  claim 1 , wherein the plurality of sensing electrodes are each formed in a rectangular strip shape having a longer side exist in a width direction of a front face of the head restraint, the width direction being intersecting with the height direction. 
   
   
       4 . The head restraint position adjusting device according to  claim 1 , wherein the detection circuit includes: a plurality of capacitance sensing circuits connected to the plurality of sensing electrodes in one-to-one correspondence and configured to output information indicating capacitances sensed by the sensing electrodes respectively; and an arithmetic processing circuit configured to calculate the estimated center position by comparing the capacitances based on the information from the plurality of capacitance sensing circuits and output calculation result information to the adjusting means. 
   
   
       5 . The head restraint position adjusting device according to  claim 1 , wherein the detection circuit includes: a time-division circuit connected to the plurality of sensing electrodes; a capacitance sensing circuit configured to output information indicating capacitances sensed by the sensing electrodes at different times respectively due to the time-division circuit; and an arithmetic processing circuit configured to calculate the estimated center position by comparing the capacitances based on the information from the capacitance sensing circuit and output calculation result information to the adjusting means. 
   
   
       6 . A head restraint position adjusting method, comprising:
 a sensing step of sensing capacitances between the human body and a head restraint provided on a seat of a vehicle by a plurality of sensing electrodes provided side by side in a height direction in the head restraint;   a detecting step of detecting an estimated center position, in the height direction, of a head of the human body sitting on the seat, based on sensing signals from the plurality of sensing electrodes indicating the capacitances sensed in the sensing step; and   an adjusting step of adjusting a position of the head restraint relative to the seat based on the estimated center position detected in the detecting step,   in a case (a) where there is any sensing electrode that indicates a larger capacitance value than that of its adjoining sensing electrode located under it among sensing electrodes that are located above a largest value sensing electrode, which has sensed a capacitance indicating a largest capacitance value among capacitance values of capacitances sensed by the respective sensing electrodes in the sensing step, the detecting step being operative to detect as the estimated center position, a position that horizontally corresponds to a sensing electrode that has sensed a capacitance indicating a largest capacitance value among capacitance values of capacitances sensed by any such sensing electrodes that indicate a larger capacitance value,   in any other case than the case (a), the detecting step being operative to detect a position that horizontally corresponds to the largest value sensing electrode as the estimated center position.   
   
   
       7 . The head restraint position adjusting method according to  claim 6 , wherein in the detecting step, in a case where the largest value sensing electrode is located above a predetermined sensing electrode, a position that horizontally corresponds to the largest value sensing electrode, among the plurality of sensing electrodes, is detected as the estimated center position. 
   
   
       8 . The head restraint position adjusting method according to  claim 6 , wherein the plurality of sensing electrodes are each formed in a rectangular strip shape having a longer side exist in a width direction of a front face of the head restraint, the width direction being intersecting with the height direction.